Fuses and Fuse box 101

[unhip_crayon]

Could someone please explain the purpose of a fuse box and how it works. What sort of components should be connected to the fuse box?

Thanks

 

[Silvertip]

Re: Fuses and Fuse box 101

Do you own a house? The fuse box or circuit breaker panel on a boat performs the very same functions as the fuse box in a house. It is the central electrical panel for the boat. Simply put, +12 volts and ground wires run from the battery to the fuse box or circuit breaker panel. Every 12 volt electrical device on your boat such as lights, fish finder, stereo, VHF radio, bilge pumps, live well pumps, etc are all fed from this panel. Normally one fuse protects one device but sometimes more than one device is fed by a single fuse (instruments and their lights for example). If you didn't have a fuse panel, every device would need a separate in-line fuse and all the wires for those devices would all have to run from the center/front of the boat all the way to the back where the battery normally lives. You eliminate a lot of wire with a fuse panel and having all the fuses in one spot is more convenient than trying to track down a large number of in-line fuses and the entire electrical system becomes safer and more reliable.

 

[achris]

Re: Fuses and Fuse box 101

Do you own a house? The fuse box or circuit breaker panel on a boat performs the very same functions as the fuse box in a house. It is the central electrical panel for the boat. Simply put, +12 volts and ground wires run from the battery to the fuse box or circuit breaker panel. Every 12 volt electrical device on your boat such as lights, fish finder, stereo, VHF radio, bilge pumps, live well pumps, etc are all fed from this panel. Normally one fuse protects one device but sometimes more than one device is fed by a single fuse (instruments and their lights for example). If you didn't have a fuse panel, every device would need a separate in-line fuse and all the wires for those devices would all have to run from the center/front of the boat all the way to the back where the battery normally lives. You eliminate a lot of wire with a fuse panel and having all the fuses in one spot is more convenient than trying to track down a large number of in-line fuses and the entire electrical system becomes safer and more reliable.

Well said and nicely explained... Now, explain for me why the 'people' who wire boats don't do it that way!!!

 

[jlinder]

Re: Fuses and Fuse box 101

I would add that the purpose of the fuse or circuit breaker is that in the event of a current overload that would cause the wiring to overheat (think fire) they open the circuit to prevent damage.

The rating on the fuse/circuit breaker should be no larger than the current capacity of the wiring or device it is supplying power to.

For example, if the wire going from the fuse is capable of 15 amps and the device is capable of 20 amps the fuse/CB cannot be larger than 15 amps.

 

[Silvertip]

Re: Fuses and Fuse box 101

They did up until the time that circuit breakers became available. Many boats today have a circuit breaker button beneat each switch and couple extras for circuits that don't need switches. You won't see a fuse panel when circuit breakers are used (don't need both since they accomplish the same job). In the good old days, there were few accessories on a boat so wiring was really crude and ran from the device directly to the battery. While things have become better in theory in this regard, one look under the console on new boats shows that there isn't much thought involved in making nice neat wire harnesses. Most boats are still a mess under there.

 

[unhip_crayon]

Re: Fuses and Fuse box 101

Thanks everyone, Helped a lot.

Also, what do you guys think about using a fuse boc from a car? The one I have on my boat is really shty and I want to replace it.

 

[Silvertip]

Re: Fuses and Fuse box 101

If you boat in salt water, that would be a mistake. If you are on fresh water, it will be ok but it must be placed in a protected area or corrosion will be an issue. Remember, car fuse blocks are well protected from the elements. Marine electrical equipment is designed with a wet environment in mind.

 

[fwmud]

Re: Fuses and Fuse box 101

I'm currently rebuilding a boat. Everything will be fused!
I have access to lots of wire so I always oversize it by one gauge.
Fire in a boat is bad.
Course you knew that already.
Hope this helps.